Terra Magazine » Honeybee Researchhttp://oregonstate.edu/terra
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High Beamshttp://oregonstate.edu/terra/2014/01/high-beams/
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For a place that takes pictures with what amounts to controlled bursts of lightning, the lab is quiet, almost hushed. Standing in the entrance to Oregon State University’s Electron Microscopy Facility (EMF), you might hear researchers’ soft voices as they discuss the best way to see pollen on a bee’s tongue or to look at a layer of molecules on a silicon wafer. You might be struck by the images on the walls and display screens — disc-shaped blood cells, elegant ocean plankton, flower-shaped nanocrystals.

The EMF is home to machines with names like Titan, Nova and Quanta, all built by FEI, a global scientific instrument company headquartered in Hillsboro, Oregon. In essence, this lab is the Hubble Telescope of the nanorealm. It reveals microorganisms associated with disease, biodiversity and pollination. It demonstrates human innovation at the molecular scale, the architecture of materials designed for industries that are just a gleam in a researcher’s eye.

The technology is a far cry from what you might have used in your high school biology lab. Researchers don’t peer at a sample through a microscope lens. They place it in a sealed chamber and sit at a computer. They direct the machine to shoot an electron beam at the sample through a tube that guides and focuses the beam with magnetic “lenses.” As the subatomic particles strike the sample, they knock other electrons off its surface. A detector captures these “secondary electrons,” and an image appears on a display screen in front of the scientist.

The EMF’s two staff members — Pete Eschbach, director, and Teresa Sawyer, instrument manager — assist scientists and train students to prepare their samples. Over the last four years, Eshbach says, the EMF has provided direct support for more than $100 million in Oregon State research projects. Its images and data underlie advances in solar energy, crop science, archaeology and human and animal health. Businesses use the facility to assure the quality of their products, and lawyers use it in disputes over pollution and patent rights.

Engineers bring in fiberglass strands, semiconductors layered with titanium-coated diatoms and piezoelectric materials, substances that change shape under the influence of an electric current. A researcher in OSU’s J.L. Fryer Salmon Disease Lab brings in a Willamette River carp that is covered in tumors, from skin to gills to throat. (The lab’s images identified the cause: an infectious parasite.)

The EMF’s two workhorses — the scanning electron microscope (SEM) and the transmission electron microscope (TEM) — differ in the power of their sample penetration. Both record the interaction of electrons with molecules, but the SEM looks at the surface, capturing images of shape and structure. The TEM dives deep for a look inside. Working with the TEM takes longer, says Eschbach, but can generate more information about composition and chemistry.

For Sawyer, the ability to generate an intimate view of materials and living things still inspires her. “It’s pretty amazing that you can get a picture with electrons,” she says. “When you hit something with electrons, they excite other electrons and you get an image. I think that’s absolutely cool.”

As honeybees pick up pollen and nectar, they pollinate about one-third of the plants in the human diet. “Growers rent honeybees to pollinate their crops, and we are taking a close look to see what kinds of pollen the bees are actually collecting,” says Sujaya Rao, entomologist in Crop and Soil Science.

Using a scanning electron microscope, Rao, graduate student Sarah Maxfield-Taylor and emeritus entomologist Bill Stephen have studied pollen collected by honeybees and bumblebees in and near blueberry and red-clover fields. They have focused on pollen caught in hair on body parts such as the leg and head, rather than on the “pollen load,” a ball made of nectar and pollen that bees take back to the hive.

Even the tongue accumulates pollen grains, which rub off the plant as the insects work their way into flowers and use their tongues to collect nectar. Bumblebees tend to have longer tongues, says Stephen, which are well adapted to specific types of flowers.

Their images show how pollen picked up by the bees can vary depending on which plants are in bloom. These show pollen on a bee’s legs, head and tongue.

]]>http://oregonstate.edu/terra/2014/01/proof-of-pollination/feed/0The Secret Life of Honeybeeshttp://oregonstate.edu/terra/2011/07/sweet-secrets/
http://oregonstate.edu/terra/2011/07/sweet-secrets/#commentsTue, 05 Jul 2011 23:16:42 +0000http://oregonstate.edu/terra/?p=7734[Editor's note: Amy Schneider is a senior in zoology. She plans to attend graduate school in journalism.]

Strapped into a small holding device, the honeybee amiably wiggles its antennae. Like a toddler in a highchair, it seems to reach greedily for the dropper with sugar water that appears over its head. As its mouth opens, its tongue darts out for a taste of the sweet liquid.

As part of Ramesh Sagili's experiments to understand honeybee behavior, bees wait in this feeding tube to receive sugar solutions. (Photo courtesy of Ramesh Sagili)

This isn’t just a strange way to treat a honeybee to lunch. It’s all part of Ramesh Sagili’s effort to understand honeybee behavior, and in particular, the reason for their sudden disappearance. Since the emergence of Colony Collapse Disorder in 2006, entire hives of honeybees have been dying with no obvious explanation.

Honeybee decline could seriously damage agricultural crops across the nation. Take the $2 billion California almond industry, which depends heavily on domestic honeybees to pollinate almond crops. Every February, 1.5 million honeybee hives are trucked from all over the country to pollinate the thousands of acres of almonds.

“Without honeybees, there is no almond crop in California,” says Sagili, an assistant professor in horticulture and the OSU Extension honeybee specialist. “In the U.S., it would be highly improbable to rely on hand pollination because the work is so expensive and labor intensive. These plants have coevolved with bees, and the bees do a much more efficient job than humans.”

According to the U.S. Department of Agriculture, honeybees pollinate 90 percent of the country’s apple and blueberry crops and are partially responsible for pollinating oranges and peaches. In fact, honeybees play a part in pollinating at least 130 U.S. crops. Since about one-third of our food depends on bees for pollination, a decline in honeybee hives would be disastrous.

Vanishing Act

And yet, that’s exactly what is happening. In late 2006, honeybees began to vanish from their hives at unprecedented and inexplicable rates. Beekeepers around the country were mystified when they opened their bee boxes, finding all the adult bees missing and only the queen and larvae remaining. Even stranger was that the absent bees were nowhere to be found, dead or alive. They were simply gone.

Researchers were hard-pressed to explain this phenomenon. Colony numbers were dropping 30 to 60 percent in some areas of the country, and the future of a $20 billion industry was at stake. That was four years ago, and scientists are still searching for a solution to the mystery.

When Colony Collapse Disorder (CCD) first gained attention, Sagili was working at Texas A&M University. At the time, researchers were not focusing on honeybee sustainability. “Because we weren’t seeing big losses, we were trying to increase colony productivity for the farmers,” Sagili says.

As CCD hit, Sagili realized that he needed to shift gears and focus on honeybee health. Oregon State University hired him in 2009 to work with Oregon beekeepers and to study colony health and vitality.

“I had to change direction completely,” Sagili adds, referring to his new studies that revolve primarily around diagnosing what is wrong with the bees.

At OSU, Sagili is the Sherlock Holmes of honeybees. He searches for clues in the insects themselves, collecting honeybees from around the state. He keeps in touch with about 25 of the state’s commercial beekeepers through email or conferences. Twice a year, he and his colleagues at the OSU Honey Bee Lab examine the collected bees for levels of mite infestation, fungal spores and protein content in food-producing glands.

The first two categories seem relatively straightforward. It makes sense that mites, Nosema (a type of fungus) spores or other parasites would harm bee health and make them less successful. But glandular protein content is particularly important because it deals with nutrition, and as Sagili says, “Everything boils down to nutrition.”

Stress in the Orchard

Modern agriculture may put stresses on honeybees that they don’t face in nature. For example, almond trees in California are practically the only plants blooming in February when bees are trucked in for pollination. Consequently, the bees acquire little but almond pollen for an entire month.

That’s a problem, says Sagili, because just like humans, bees require a balanced diet. Some amino acids, the building blocks of protein, must come from food; neither people nor bees synthesize all the ones they need. Bees need 10 amino acids in their diet for full development, and since their only protein source is pollen, collecting a variety of pollens is crucial to proper nutrition.

Bees eating only almond pollen are like people living only on French fries. A diet composed of single source pollen does not provide enough nutrients, and, suggests Sagili, may weaken the bees’ immune system.

Poor immune systems leave honeybees greatly susceptible to parasites and disease. While these threats are nothing new, unhealthy and nutritionally deficient bees could be falling prey to old pests as their defenses are being drained.

That’s why Sagili is interested in finding a connection between bee protein and immune systems. Poor nutrition might help to explain why bees are disappearing. The other pressures on bees — parasites, viruses and pesticides — are potential contributing factors, and CCD may be the ultimate result of all of them.

Taste Test

Sagili is performing experiments to narrow down the possibilities. In one, he places bees in a “containment tube” and offers them different concentrations of a sugar solution. This taste test, with the bees waiting patiently and wriggling their antennae in anticipation, allows Sagili to learn more about their ability to detect sugar concentrations. Because worker bees have specialized jobs in the hive, some can detect higher concentrations better than others. It’s possible that nutritional stress may affect important foraging behavior of honeybees.

“Once we gather some good information from the past two years, we can see if there’s a correlation between survival status of the hive and all the problems that we found in the hives, such as protein content,” Sagili says.

Meanwhile, as Sagili and other scientists learn more about honeybees and their behavior, the number of hives continues to dwindle, from about 5 million in 1950 to 2.4 million in 2010. If Sagili is right and nutrition is the most significant problem, then beekeepers, farmers and orchard managers may be able to reverse that trend by ensuring that their pollinators are well fed.

Ramesh Sagili will work with Oregon farmers whose crops depend on bee pollination. In his research, Sagili will study pheromones, chemicals that affect animal behavior.

Ramesh Sagili arrived in Corvallis in February to start a honeybee research program targeting mites, pesticides, stress and nutrition. The new OSU bee specialist is part of an initiative to help ensure that there are enough healthy honeybees to pollinate Oregon’s crops.

Sagili says Varroa mites, nutritional deficiencies or other factors might be the cause of colony collapse disorder, which occurs when adult honeybees abandon a hive. Sagili’s position was created at the request of Oregon agricultural groups worried about the health and supply of honeybees, which are crucial pollinators for many of the state’s crops, including blueberries, pears, cherries, apples and vegetable seeds.

“Colony collapse disorder is so complex that it will be a long time before we arrive at a conclusion as to what is causing it,” Sagili adds. “But meanwhile, beekeepers need to take steps to maintain healthy and strong colonies.”